The need to provide reliability between communications nodes on networks has been known and understood for some time. As such, network designs often provide for protection paths across such networks in the event of failures.
For example, synchronous optical networks (“SONET”) and asynchronous transfer mode (“ATM”) networks include protection switching used to provide 1+1, 1:1, 1:n, or m:n redundancy for provisioned paths across SONET and ATM networks. In the event of a fault, exemplified by failed or degraded signal, traffic from a working path may be switched to a provisioned protection path, thereby limiting the effects of a fault.
In the past, existing protocols have required manual configuration of working and protection paths across the network. Network topologies were relatively simple, and configuration was straightforward. More recently conceived networks allow paths to be established dynamically, and automatically as required. This provides great flexibility in configuring the network to provide working and protection paths only as required.
However, provisioning network resources to effectively provide sufficient redundancy for protection switching without unnecessarily reserving network resources presents new challenges for network operators and architects. This is particularly so for modern mesh networks, in which each network node may have links to multiple adjacent nodes, and multiple paths between source and destination nodes exist.
Accordingly, there is a need for new network protocols, methods and devices that make efficient use of network resources while allowing protection switching.